Steve Atkins <steve@xxxxxxxxxxx> writes: >> On Jan 20, 2017, at 7:03 PM, btober@xxxxxxxxxxxx <btober@xxxxxxxxxxxxxxx> wrote: >> >> While learning a bit about basic hot standby configuration, I was reviewing an article that used these parameters >> >> wal_level = 'hot_standby' >> archive_mode = on >> archive_command = 'cd .' That's just a very silly way of making archive_command a true no-op... I would have set it to '/bin/true' >> max_wal_senders = 1 >> hot_standby = on >> >> >> How or why that particular archive_command actually works (... and it does ... I tried it ...) is not clear to me based on reading of the Postgresql documentation on this topic. I would have expected to see an actual copy or rsync command, as described in the fine manual at section 25.3.1. "Setting Up WAL Archiving" >> >> The entire example appears at >> >> https://www.digitalocean.com/community/tutorials/how-to-set-up-master-slave-replication-on-postgresql-on-an-ubuntu-12-04-vps >> >> Can anyone enlighten on this topic, or provide a link to an existing explanation? > > It's not archiving logs at all, instead relying on streaming them directly to the slave. > > Changing archive_mode requires a server restart, while changing archive_command from a command that does nothing, successfully, to a command that actually archives logs just requires a reload. So this lets you enable archiving without halting the server by changing the command. > > Or that's how I vaguely recall it working some years ago. Things may have changed now - you're following a very old tutorial. > > Cheers, > Steve -- Jerry Sievers Postgres DBA/Development Consulting e: postgres.consulting@xxxxxxxxxxx p: 312.241.7800 -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
